Methods for the preparation poly(etherimide)s

ABSTRACT

A new method for the synthesis of poly(etherimide)s comprises transimidation of bis(imide) (IV)                    
     in the presence of a substituted phthalic anhydride or 4-substituted tetrahydrophthalic anhydride to yield dianhydride (V)                    
     which may then be reacted with a diamine to produce poly(etherimide)s. By-product substituted N-alkylphthalimide or 4-substituted N-alkyltetrahydrophthalic anhydride may be recycled or converted to 4-substituted N-alkylphthalimide for use in the formation bisimide (IV), obviating the need for a nitration step.

BACKGROUND OF THE INVENTION

This invention relates to a method for the manufacture ofpoly(etherimide)s. More particularly, it relates to a method for themanufacture of poly(etherimide)s which eliminates the need for anintermediate nitration step.

Polyetherimides are high heat engineering plastics having a variety ofuses. As disclosed in U.S. Pat. Nos. 4,417,044; 4,599,429; 4,902,809;and 4,921,970, the present commercial process for the synthesis ofpolyetherimides requires nitration of N-methylphthalimide to yield4-nitro-N-methylphthalimide. Nitration often results in the formation ofbyproducts, which must be separated. In the next step of the process,4-nitro-N-methylphthalimide is treated with the disodium salt of adihydroxy compound, usually a bis(phenol) such as bisphenol A, to yielda bisimide (I) having the following general structure:

Suitable displacement reactions are disclosed in U.S. Pat. No.4,257,953. Displacement is also disclosed in U.S. Pat. Nos. 5,132,423and 5,872,294. Bisimide (I) is then reacted with a phthalic anhydride inan exchange reaction as disclosed in U.S. Pat. Nos. 4,318,857,4,329,291, 4,329,292, 4,329,496, and 4,340,545 to yield the dianhydride(II):

Reaction of dianhydride (II) with a diamine results in polymerization toa poly (etherimide). Methods which improve or even eliminate any of thepreceding steps would result in an improved synthesis ofpoly(etherimide)s.

SUMMARY OF THE INVENTION

A new method for the synthesis of poly(etherimide)s which eliminates thenitration step comprises synthesis and reaction of a substitutedN-alkylphthalimide (III)

with the disodium salt of a dihydroxy compound such as a bis(phenol) toyield the bis (imide) (IV)

Bis(imide) (IV) is then subjected to transimidation to yield thedianhydride (V)

Transimidation is effected in the presence of a substituted phthalicanhydride, which yields a substituted N-alkylphthalimide thatcorresponds to the substituted phthalic anhydride as a by-product.By-product substituted N-alkylphthalimide may then be recycled for usein the formation bisimide (IV).

In another embodiment, transimidation is effected in the presence of4-substituted tetrahydrophthalic anhydride, which yields a 4-substitutedN-alkyltetrahydrophthalimide as a by-product. The by-product4-substituted N-alkyltetrahydrophthalimide may be converted byaromatization to a 4-substituted N-alkylphthalimide, which may be usedin the formation of bis(imide) (IV).

Finally, the reaction of dianhydride (V) with a diamine (VI) having thestructure

H₂N—R—NH₂  (VI)

yields poly(etherimide)s. This route obviates the need for theintermediate nitration step required by the prior art synthesis.

DETAILED DESCRIPTION

A convenient route for the manufacture of poly(etherimide)s comprisessynthesis and reaction of a substituted N-alkylphthalimide (III):

wherein the alkyl group is a branched or straight chain alkyl grouphaving from one to about 1 8 carbons. Preferably, the alkyl group is amethyl group. The substituent (X) is a nitro, chloro, bromo, or fluoroin the 3- or 4-position. Substituted N-alkylphthalimides may be obtainedby the treatment of the corresponding substituted phthalic anhydridewith a primary amine having the formula H₂N-alkyl via a melt reaction,for example by contact of a gaseous primary amine such as methylaminewith molten 4-halophthalic anhydride. Halophthalic anhydrides may beobtained by aromatization of the corresponding halotetrahydrophthalicanhydrides as disclosed in U.S. Pat. Nos. 5,233,054, 5,003,088,5,059,697 and 4,978,760, which are incorporate by reference herein.Halophthalic anhydrides may also be obtained by the aromatization of thecorresponding halotetrahydrophthalic anhydrides in the presence of acatalyst such as a transition metal oxide. Nitro substituted phthalicanhydrides may be obtained by the nitration of phthalic anhydrides astaught in U.S. Pat. No. 5,155,234.

Displacement of the substituent of the substituted N-alkylphthalimide(III) may be effected by treatment with the disodium salt of a dihydroxycompound having the formula (VII)

HO—S—OH  (VII)

to yield the bis(imide) (IV)

wherein S is a divalent radical, for example a straight or branchedchain alkylene group having from about 2 to about 20 carbon atoms; acycloalkylene group having from about 3 to about 20 carbon atoms; or anarylene group having from 6 to about 20 carbon atoms, and halogenatedderivatives thereof. The alkylene, cycloalkylene, and arylene groups maybe further substituted with alkyl, halogenated alkyl, fluoro, alkoxy,nitro, phenyl, phenoxy, aryl or other groups, provided that suchsubstitutions do not interfere with synthesis or reaction. Thedisplacement reaction between the dihydroxy compound and the substitutedN-alkylphthalimide may be conducted in an inert solvent such as toluene,xylene, chlorobenzene or dichlorobenzene in the presence of a phasetransfer catalyst such as hexaethylguanidinium chloride at a temperaturein the range of about 110 to about 180° C. as taught in U.S. Pat. No.5,132,423, which is incorporated by reference herein. Displacement mayalso occur in the melt phase with the substituted N-alkyphthalimide.

A particularly preferred dihydroxy compound is bis(phenol) (VIII)

wherein T is a single bond linking the two aryl groups, or a divalentradical, for example a straight or branched chain alkylene group havingfrom one to about 20 carbon atoms; a cycloalkylene group having fromabout 3 to about 20 carbon atoms; or an arylene group having from 6 toabout 20 carbon atoms, and halogenated derivatives thereof. Thealkylene, cycloalkylene, and arylene groups may be further substitutedalkyl, halogenated alkyl, fluoro, alkoxy, nitro, phenyl, phenoxy, arylor other groups, provided that such substitutions do not interfere withsynthesis or reaction. T further includes divalent functional groupssuch as sulfide, carbonyl, sulfoxide, and ether and divalent radicals offormula (XV)

Illustrative examples of bis(phenol)s of formula (VIII) include2,2-bis[4-hydroxyphenyl]propane; 4,4′-bis(4-hydroxyphenyl)di phenylether; 4,4′-bis(4-phenoxy)diphenyl sulfide;4,4′-bis(4-hydroxyphenyl)benzophenone ;4,4′-bis(4-hydroxyphenyl)diphenyl sulfone;2,2-bis[4-(3-hydroxyphenyl)phenyl]propane;4,4′-bis(3-hydroxyphenyl)diphenyl ether;4,4′-bis(3-hydroxyphenyl)diphenyl sulfide;4,4′-bis(3-hydroxyphenyl)benzophenone; 4,4′-bis(3-hydroxyphenyl)diphenylsulfone; 4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl-2,2-propane;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)di phenyl ether; 4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfide;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl) benzophenone, and4-(hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfone dianhydride, aswell as various mixtures thereof. These and other bis(phenol)s anddihydroxy compounds are described in U.S. Pat. Nos. 3,972,902 and4,455,410.

Bis(imide) (IV) is treated with a substituted phthalic anhydride (IX)

via transimidation to yield dianhydride (V)

wherein S is as described above. Useful substituted phthalic anhydrideshave a nitro, chloro, bromo, or fluoro group in the 3 or 4 positionalthough chloro and bromo substituents are preferred. Also preferred aremixtures of structural isomers, for example a mixture comprising3-halophthalic anhydride and 4-halophthalic anhydride. Surprisingly,reaction conditions may be adjusted so as to minimize the formation ofthe N-alkylamino-N-alkylphthalimide (from the displacement of the halogroup with alkylamine), a highly colored by-product which can impart anundesirable color to the product dianhydride. Preferably, the YI of theproduct is less than about 25, and more preferably less than about 15 asmeasured by the UV spectrum of the product.

A desired by-product of this reaction is substituted N-alkylphthalimide(III), which may be isolated and used for reaction with a dihydroxycompound (VII) as described above.

In an alternative embodiment, transimidization of bis(imide) (IV) iseffected in the presence of 4-substituted tetrahydrophthalic anhydride(X)

Useful substituents are nitro, chloro, fluoro and bromo. Chloro andbromo substituents are preferred. 4-substituted tetrahydrophthalicanhydride (X) is available from the Diels-Alder condensation of thedienophile maleic anhydride with the 2-substituted-1,3-butadiene.Conditions for this reaction are known in the chemical literature.

The by-product of this transimidization is a 4-substitutedN-alkyltetrahydrophthalimide (XI)

4-substituted N-alkyltetrahydrophthalimide (XI) may be converted byaromatization to 4-substituted N-alkylphthalimide, which can be used inthe displacement reaction with the dihydroxy compound as describedabove. Aromatization may be achieved by any method known in the art suchas those taught by U.S. Pat. Nos. 5,233,054, 5,003,088, 5,059,697, and4,978,760. Alternately, aromatization can be achieved in the presence ofa transition metal oxide catalyst such as vanadium oxide (V₂O₂) at atemperature in the range of about 250° C. to about 270° C.

Transimidization with either substituted phthalic anhydrides (IX) or4-substituted tetrahydrophthalic anhydride (X) may be conducted in aninert solvent such as water in the presence of a base such astriethylamine at a temperature in the range from about 150 to about 250°C., and preferably in the range from about 160 to about 180° C. Forexample, transimidation is effected by reaction of bis(imide) (IV) witha 6-7 fold molar excess of substituted phthalic anhydride (IX) or4-substituted tetrahydrophthalic anhydride (X) in water in the presenceof at least one mole of base, e.g., triethylamine, per mole of anhydrideat about 170° C. for about one to about 1 to 2 hours.

Preferably, the aqueous reaction mixture is then continuously extractedin a packed column with an organic solvent, e.g., toluene, containing abase such as triethylamine to remove unconverted bis(imide) (IV) and theformed substituted N-alkylphthalimide (III) or 4-substitutedN-alkyltetrahydrophthalimide (XI). Transimidation may continue withinthe column. The aqueous eluent from the column contains the tetraacid ofdianhydride (V) and substituted phthalic diacid, both present as baseconjugated salts. The aqueous solution is fed to a flash distillationvessel whereby a majority of the water and some of the base is removed.The bottoms from this vessel are fed to a wiped film evaporator undervacuum, where the base conjugated salts crack to liberate base withconcomitant ring closure of diacids and tetraacids to anhydride anddianhydride. Water, base, and substituted phthalic anhydride or4-substituted tetrahydrophthalic anhydride are taken overhead. Thedianhydride is isolated as a molten liquid from the bottom of the wipedfilm evaporator. The base, water, and the substituted phthalic anhydrideor 4-substituted tetrahydrophthalic anhydride from the flash vessel andfrom the wiped film evaporator are recycled back to the exchangereactor.

Preferably, the organic eluent from the extraction process is fed to aflash vessel wherein the solvent and the base are removed from theheavier organics. These overheads are recycled back to the bottom of theexchange column. The bottom from this flash vessel is fed to anotherflash vessel where substituted N-alkylphthalimide, when present, (or4-substituted N-alkyltetrahydrophthalimide) is (III) taken over head.Substituted N-alkylphthalimide may then be purified before being reusedin the displacement reaction. When 4-substitutedN-alkyltetrahydrophthalimide is present it must first be converted byaromatization to 4-substituted N-alkyl phthalimide then used in thedisplacement reaction. The bottom of the flash vessel primarily containsprimarily recycled bis(imide) (IV), imide-anhydride (bisimide whereinonly one of the imides has been converted to an anhydride), and somesubstituted N-alkylphthalimide (III) or 4-substituted N-alkylphthalimide. These may be cycled back to the exchange reactor.

Dianhydride (V) may then be reacted with diamine (VI) to yieldpoly(etherimide)s. Diamine (VI) has the structure

H₂N—R—NH₂  (VI)

wherein R in formula (VI) includes but is not limited to substituted orunsubstituted divalent organic radicals such as: (a) aromatichydrocarbon radicals having about 6 to about 20 carbon atoms andhalogenated derivatives thereof; (b) straight or branched chain alkyleneradicals having about 2 to about 20 carbon atoms; (c) cycloalkyleneradicals having about 3 to about 20 carbon atoms, or (d) divalentradicals of the general formula (XII)

wherein Q includes but is not limited to divalent a divalent moietyselected from the group consisting of —O—, —S—, —C(O)—, —SO₂—,C_(y)H_(2k)— (y being an integer from 1 to 5), and halogenatedderivatives thereof, including perfluoroalkylene groups.

Any diamino compound may be employed. Examples of suitable compounds areethylenediamine, propylenediamine, trimethylenediamine,diethylenetriamine, triethylenetetramine, hexamethylenediamine,heptamethylenediamine, octamethylenediamine, nonamethylenediamine,decamethylenediamine, 1,1 2-dodecanediamine, 1,18-octadecanediamine,3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,4-methylnonamethylenediamine, 5-methylnonamethylenediamine,2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine,2,2-dimethylpropylenediamine, N-methyl-bis(3-aminopropyl) amine,3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy) ethane,bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine,bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine,2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine,p-xylylenediamine, 2-methyl-4,6-diethyl-1,3-phenylene-diamine,5-methyl-4,6-diethyl-1,3-phenylene-diamine, benzidine,3,3″-dimethylbenzidine, 3,3″dimethoxybenzidine, 1,5-diaminonaphthalene,bis(4-aminophenyl) methane, bis(2-chloro-4-amino-3, 5-diethylphenyl)methane, bis(4-aminophenyl) propane, 2,4-bis(b-amino-t-butyl) toluene,bis(p-b-amino-t-butylphenyl) ether, bis(p-b-methyl-o-aminophenyl)benzene, bis(p-b-methyl-o-aminopentyl) benzene,1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide,bis(4-aminophenyl) sulfone, bis(4-aminophenyl) ether and1,3-bis(3-aminopropyl) tetramethyldisiloxane. Mixtures of thesecompounds may also be present. The preferred diamino compounds arearomatic diamines, especially m- and p-phenylenediamine and mixturesthereof.

All patents cited herein are incorporated by reference.

The invention is further described by the following non-limitingexamples:

EXAMPLES

Batch transimidation (exchange) reactions were conducted in a Parrapparatus of 600 mL capacity with two quartz oblong windows on theopposite sides of the vessel, equipped with a glass liner, a watercooled magnetic drive device (modified such that all internal bearingsurfaces were Teflon) which was speed controlled and a heating mantlecontrolled by a temperature controller. A thermocouple was fitted to oneof ports on the reactor head, another port was fitted with a 680 psirupture disc (rated at 170° C.), and another port was fitted with a diptube (⅛ inch 316 stainless steel) running to the bottom of the reactor.The dip tube port was used for the aqueous phase manipulation,introduction of the organic phase to the reactor, and for maintainingpressure during the extraction procedure. A zero volume coupling wasconnected to a nitrogen line equipped with a pressure indicator, a 580psi relief spring valve, and appropriate needle valves for purging andplacing the reactor under an inert atmosphere, e.g., nitrogen.

A second, 2-liter Parr apparatus, equipped with a magnetic, water-cooledagitator, a thermocouple, and a dip tube was used for pre-mixing theanhydride, triethylamine, and water. The line from the 2-liter Parr tothe 600 mL Parr was ¼ inch 316 stainless wrapped with electrical heattape and insulated. The temperature of the vessel was controlled at 190°C.

A typical experimental procedure is as follows. Finely ground bis(imide)(XIII)

(typically 25.7 g) was charged to the 600 mL Parr, and after replacingthe atmosphere with nitrogen, the temperature of the Parr was raised to1 70° C. The contents of the vessel were isolated with needle valves andagitated. The second, 2-liter Parr was charged with an aqueous mixtureof phthalic anhydride or 4-chlorophthalic anhydride, triethylamine (TEA)and water, and any additional anhydride (typically 320 grams of aqueoussolution comprising 19.8% anhydride, 17.9% triethylamine, balance water,5.5 grams of additional anhydride). The water was degassed with nitrogenor helium prior to the addition of 4-chlorophthalic anhydride, which wasfollowed by the addition of triethylamine. The contents of this vesselwere isolated using the needle valves, placed under an inert atmosphereand then heated to 180° C. Pressure typically rose to 190 psi.

The contents of the 2-liter Parr were then transferred to the 600 mLParr with nitrogen pressure, except for about 14 g, which remained inthe second Parr. The contents of 600 mL Parr were maintained at 170° C.The reaction mixture went clear within 22 minutes. Approximately 2-mLsamples of the reaction mixture were taken through a long dip tube whilemaintaining an inert atmosphere. The dip tube temperature was alsomaintained at about 180° C. The cooled samples were analyzed by infraredspectroscopy to determine the percent exchange.

Example 1 Batch Transimidation with 4-Chlorophthalic Anhydride

4-Chlorophthalic anhydride was reacted as described above on alaboratory scale with bis(imide) (XIII) in water and in the presence ofTEA, in which the molar ratio of 4-chlorophthalicanhydride:triethylamine:bis(imide) was 7.7:11.55:1 at 7.3% solids. About70% exchange occurred in one hour at 170° C. to ultimately yield productdianhydride (XIV)

Percent solids are defined as the weight of BPA bis(imide) (XIII)divided by the total weight of solution.

Example 2 Optimization of Transimidation Using 4-ChlorophthalicAnhydride

A series of batch laboratory exchange reactions were performed in orderto define optimal operating parameters for transimidation using4-chlorophthalic anhydride (CIPA), and in particular to determine thereaction rate and molar ratio of 4-chlorophthalic anhydride: bis(imide)(XIII) (BI) required to achieve 65-70% exchange. Formulations are shownin Table 1, and results are shown in Table 2.

TABLE 1 Final CIPA:BI Final TEA:CIPA CIPA:TEA:BI No. Molar Ratio MolarRatio Molar Ratio % Solids 1 5.2:1 1.0:1 5.2 5.1 1.0 14.2 3 6.3:1 1.0:16.3 6.0 1.0 12.3 5 5.7:1 1.5:1 5.7 8.6 1.0 10.0 10 7.7:1 1.5:1 7.7 11.51.0 7.6 12 8.6:1 1.5:1 8.6 12.9 1.0 6.9

TABLE 2 Example Percent Exchange at Time (Minutes) (as determined by IR)Number 20 25 30 40 50 60 70 80 90 100 110 120 150 160 1 1.0 3.3 7.6 15.824.9 33.5 40.3 45.2 49.6 53.3 54.4 56.0  ns* ns 3 6.6 13.5 16.2 24.131.3 39.2 43.8 49.1 51.7 54.8 56.0 59.1 62.7 ns 5 37.7 53.0 58.3 61.762.5 62.8 62.4 63.0 62.7 62.7 62.6 62.7 ns ns 10 51.1 62.0 66.7 62.268.9 67.1 68.9 69.2 69.1 69.4 69.2 69.6 ns 69.7 12 60.9 68.5 70.5 70.771.6 71.6 71.0 71.6 71.6 71.4 71.3 71.2 ns 71.4 *not sampled

As the above data show, a molar ratio of about 6:1 of anhydride tobis(imide) was required to achieve 62.8% exchange in one hour, and amolar ratio of 7.67:1 is required to achieve 69.5% exchange in 70minutes.

Example 3 Transimidation/Extraction

Transimidation reactions followed by continuous extraction to isolatethe product dianhydride were conducted in an apparatus similar to thatused for batch transimidation, except that the dip tube protruded intothe reactor only about one-third of the way, and the reactor was furtherfitted with a ⅛-inch 316 stainless steel tube extending to the bottom ofthe reactor. This tube was connected to a high pressure liquidchromatography (HPLC) system capable of delivering 40 mL per minute viaof ½-inch 316 stainless steel tubing wrapped with electrical heatingtape. This allowed delivery of the toluene/triethylamine extractionsolution to the bottom of the reactor, while the organic phase exitedthrough the dip tube, which had a needle valve plumbed to an externalcooling bath, and then to a collection vessel. A recirculation loop onthe toluene feed line was used to purge oxygen from the toluene feedequipment.

In a typical procedure, the reactor was charged with the reactants asdescribed above, (typically 17.0 g of bis(imide) (XIII) (BI) and 9.0 gof anhydride (4-chlorophthalic anhydride unless otherwise indicated) in100 g of an aqueous solution comprising 18 wt. % triethylamine, 16.5 wt.% anhydride, with the balance being water), yielding a final molar ratioof TEA:anhydride of about 1.1:1.

After reaction was completed, agitation was decreased to 10%, and about1 liter of solution comprising about 2-3 wt. % triethylamine in toluenesparged with nitrogen was pumped into the Parr reactor at 20 ml/minuteat 160-170° C. The toluene phase exited the reactor through the dippipe. The exit flow rate was controlled by a needle valve on the exitline. The exit flow rate was made to match the feed rate of thetoluene/TEA solution. Extraction was allowed to proceed for about 1hour. After extraction, agitation was decreased and the contents of thereactor were cooled to about 85° C. The contents of the reactor werethen transferred under an inert atmosphere to a 500-mL flask equippedwith a bottom drain, and the phases were allowed to separate.

A portion of the aqueous phase (typically 17 to 25 mL) was thendevolatized by charging to a clean 250-mL one-necked round-bottomedflask which was maintained under an inert atmosphere. The flask wasplaced in a GC oven and attached to a glass duel bulb Kugelrohr typeextension on the outside of the oven using a glass extension piece. Thedual bulb was cooled with an external dry ice/methylene chloride bathand attached to a Kugelrohr oscillating drive which was itself connectedto a direct drive vacuum pump protected by a dry ice trap.

The flask was placed slowly under full vacuum (generally 0.1 mm Hg orless) and the GC oven temperature program was slowly heated to 240° C.The total time in the oven was about one hour. The oven door was openedat the conclusion of the temperature program and the flask was allowedto air cool. Solidified dianhydride was removed from the flask andanalyzed by IR spectroscopy to determine the percent exchange and thecomposition, respectively. Yellowness Index was determined by ASTMD1925.

Formulations and results are shown in Table 3 below.

TABLE 3 Anhydride: TEA: Anhydride: % BI Molar Anhydride TEA:BI So- No.Ratio Molar Ratio Molar Ratio lids Yield** YI 14 6.0:1 1.5:1 6.0 9.0 1.09.6 90.6 39.0 16 6.0:1 1.1:1 6.0 6.6 1.0 11.8 95.3 15.4 18 6.0:1 1.5:16.0 9.0 1.0 9.6 94.0 39.0 72* 5.0:1 1.1:1 5.0 5.5 1.0 14.5 96.7 12.0 75*5.0:1 1.1:1 5.0 5.5 1.0 14.5 95.9 12.0 78* 5.0:1 1.1:1 5.0 5.5 1.0 14.595.0 10.4 80* 5.0:1 1.1:1 5.0 5.5 1.0 14.5 96.1 8.0 83 5.0:1 1.1:1 5.05.5 1.0 14.5 94.6 7.0 *Control using phthalic anhydride **PercentExchange on final product after completion of extraction

Further analysis indicated that product dianhydride (XIV) having lowcolor (YI 15.4) was isolated from a batch exchange reaction run at a 6:1molar ratio of anhydride:bis (imide) (XIII) at 170° C., using a molarratio of 1.1:1 triethylamine:anhydride for one hour, followed by tolueneextraction and laboratory dianhydride isolation. Product dianhydride(XIV) having even lower color (YI 7) was isolated from a batch exchangereaction run at a 5:1 molar ratio of anhydride:bis(imide) (XIII), with amolar ratio of 1.1:1 triethylamine:anhydride and using 14.46% solids inthe exchange reaction for 1 hour at 170° C., followed by 2%triethylamine in toluene extraction. Extent of exchange was about 52%.Conventional laboratory transimidation using phthalic anhydride andbis(imide) (XIII) yield product dianhydrides with a YI of 8 to 12.

Example 4 Transimidation with 4-halotetrahydrophthalic Anhydride

A Parr apparatus was charged with 100 mL of water, 12.0 g of bisimide(XIII), 32.8 g of 4-chlorotetrahydrophthalic anhydride, and 21.4 g oftriethylamine. The molar ratio of 4-chlorotetrahydrophthalicanhydride:triethylamine:bisimide was 8:9.63:1. The vessel atmosphere wasreplaced with nitrogen, pressurized with 30 psi of nitrogen and thenheated to 170° C. The reaction continued at 170° C. for 2.3 hours withagitation. The reaction mixture was cooled to 80° C. and the reactor wasvented. A sample of the aqueous phase was removed from the reactionvessel and heated at 350° C. on a hot plate for 10 minutes to remove4-chlorotetrahydrophthalic anhydride, the N-methyl imide of4-chlorotetrahydrophthalic anhydride, water and triethylamine. Infraredspectroscopy of the residue showed that approximately 75% exchange hadoccurred.

The remaining reaction mixture was transferred to a separatory funneland extracted once with 500 ml of toluene containing 30 ml oftriethylamine at 80° C. A portion of the extracted aqueous phase washeated at 350° C. on a hot plate for 10 minutes to remove4-chlorotetrahydrophthalic anhydride, the N-methyl imide of4-chlorotetrahydrophthalic anhydride, water and triethylamine. Infraredspectroscopy of the extracted aqueous phase residue showed thatapproximately 86% exchange had occurred.

As can be seen by the preceding examples transimidation of a bisimide(IV) with either a substituted phthalic anhydride or a 4-subsitutedtetrahydrophthalic anhydride provides a convenient, cost effective, andefficient route to poly(etherimide)s and eliminates the nitration steprequired in previous poly(etherimide) syntheses. Additionally,transimidation can result in dianhydrides with a YI of less than about25.

Example 5 Conversion of 4-chloro-N-methyl-tetrahydrophthalimide to4-chloro-N-methyl-phthalimide

Gas phase reactions were carried out in a hot-tube reactor that waspacked with about 13 grams of a catalyst containing V₂O₅. The inlet ofthe hot-tube reactor was connected to a flow controller and heatedsyringe pump. The flow controller managed the flow of purified air. Theheated syringe pump contained 4-chloro-N-methyl tetrahydrophthalimideand delivered it to the hot tube reactor at a constant rate of 0.05milliliters per minute. The outlet of the hot tube reactor was connectedto a receiver cooled in an ice-bath where the reaction products werecollected. The hot-tube reactor was maintained at the 260° C. Thereaction product was analyzed by gas chromatographic techniques afterthe system had equilibrated for 10-20 minutes. At a flow rate of 90ml/min all of the N-methyl-4-chlorotetrahydrophthalimide was convertedto N-methyl-4-chlorophthalimide.

While preferred embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

What is claimed is:
 1. A method for the synthesis of poly(etherimide)s,comprising transimidation of a bis(imide) (IV)

wherein the alkyl moiety is a straight or branched chain alkyl grouphaving from 1 to about 18 carbon atoms, and S is a divalent radicalselected from the group consisting of a straight or branched chainalkylene group having from about 2 to about 20 carbon atoms, acycloalkylene group having from about 3 to about 20 carbon atoms, anarylene group having from 6 to about 20 carbon atoms, and halogenatedderivatives thereof, with a substituted phthalic anhydride having asubstituent selected from the group consisting of nitro, bromo, fluoroand chloro to yield a dianhydride (V):

 and reaction of dianhydride (V) with diamine (VI) H₂N—R—NH₂  (VI)wherein R is selected from the group consisting divalent substituted orunsubstituted aromatic hydrocarbon radicals having about 6 to about 20carbon atoms and halogenated derivatives thereof, divalent substitutedor unsubstituted straight or branched chain alkylene radicals havingabout 2 to about 20 carbon atoms, divalent substituted or unsubstitutedcycloalkylene radicals having about 3 to about 20 carbon atoms, anddivalent radicals of the general formula (XII)

wherein Q is a divalent moiety selected from the group consisting of—O—, —S—, —C(O)—, —SO₂—, C_(y)H_(2y)— wherein y is an integer from 1 to5, and halogenated derivatives thereof.
 2. The method of claim 1,wherein transimidation with the substituted phthalic anhydride yields asubstituted N-alkylphthalimide.
 3. The method of claim 2 wherein thesubstituted N-alkylphthalimide is recycled for use in the formation ofbisimide (IV).
 4. The method of claim 1 wherein the substituted phthalicanhydride is a mixture of 3-substituted phthalic anhydride and4-substituted phthalic anhydride.
 5. The method of claim 4 wherein the3-substituted phthalic anhydride is 3-chlorophthalic anhydride and the4-substituted phthalic anhydride is 4-chlorophthalic anhydride.
 6. Themethod of claim 4, wherein transimidation yields a mixture of3-substituted N-alkylphthalimide and 4-substituted N-alkylphthalimide.7. The method of claim 6 wherein the mixture of 3-substitutedN-alkylphthalimide and 4-substituted N-alkylphthalimide is recycled foruse in the formation of bisimide (IV).
 8. The method of claim 1 whereinthe substituted phthalic anhydride is 4-chlorophthalic anhydride.
 9. Themethod of claim 8 wherein the transimidation yieldsN-alkyl-4-chlorophthalimide.
 10. The method of claim 9 wherein theN-alkyl-4-chlorophthalimide is recycled for use in the formation ofbisimide (IV).
 11. The method of claim 1, wherein the YI of the productdianhydride is less than about
 25. 12. The method of claim 1, whereinthe alkyl moiety is methyl.
 13. The method of claim 1, wherein S isderived from bisphenols having the formula (VIII):

wherein T is a single bond linking the two aryl groups, or a divalent,straight or branched chain alkylene radical having from one to about 20carbon atoms, or a divalent cycloalkylene group having from about 3 toabout 20 carbon atoms, or a divalent arylene group having from 6 toabout 20 carbon atoms, a divalent sulfide, carbonyl, sulfoxide, adivalent radicals of formula (XV)

 or a mixture thereof.
 14. The method of claim 13, wherein thebis(phenol) is selected from the group consisting of2,2-bis[4-hydroxyphenyl]propane; 4,4′-bis(4-hydroxyphenyl) diphenylether; 4,4′-bis(4-phenoxy)diphenyl sulfide; 4,4′-bis(4-hydroxyphenyl)benzophenone; 4,4′-bis(4-hydroxyphenyl)diphenyl sulfone;2,2-bis[4-(3-hydroxyphenyl)phenyl]propane;4,4′-bis(3-hydroxyphenyl)diphenyl ether;4,4′-bis(3-hydroxyphenyl)diphenyl sulfide; 4,4′-bis(3-hydroxyphenyl)benzophenone; 4,4′-bis(3-hydroxyphenyl)diphenyl sulfone;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl-2,2-propane;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl ether;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfide;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl) benzophenone, and4-(hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfone dianhydride, aswell as various mixtures thereof.
 15. The method of claim 1, whereindiamine (VI) is selected from the group consisting of ethylenediamine,propylenediamine, trimethylenediamine, diethylenetriamine,triethylenetetramine, hexamethylenediamine, heptamethylenediamine,octamethylenediamine, nonamethylenediamine, decamethylenediamine,1,12-dodecanediamine, 1,18-octadecanediamine,3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,4-methylnonamethylenediamine, 5-methylnonamethylenediamine,2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine,2,2-dimethylpropylenediamine, N-methyl-bis(3-aminopropyl) amine,3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy) ethane,bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine,bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine,2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine,p-xylylenediamine, 2-methyl-4,6-diethyl-1,3-phenylene-diamine,5-methyl-4,6-diethyl-1,3-phenylene-diamine, benzidine,3,3″-dimethylbenzidine, 3,3″dimethoxybenzidine, 1,5-diaminonaphthalene,bis(4-aminophenyl) methane, bis(2-chloro-4-amino-3, 5-diethylphenyl)methane, bis(4-aminophenyl) propane, 2,4-bis(b-amino-t-butyl) toluene,bis(p-b-amino-t-butylphenyl) ether, bis(p-b-methyl-o-aminophenyl)benzene, bis(p-b-methyl-o-aminopentyl) benzene,1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide,bis(4-aminophenyl) sulfone, bis (4-aminophenyl) ether1,3-bis(3-aminopropyl) tetramethyldisiloxane, and mixtures thereof. 16.The method of claim 1, wherein diamine (VI) is m-phenylenediamine,p-phenylenediamine, or a mixture thereof.
 17. A method for the synthesisof poly(etherimide)s, comprising transimidation of a bis(imide) (IV)

wherein the alkyl is moiety is a straight or branched chain alkyl grouphaving from 1 to about 18 carbon atoms, and S is a divalent radicalselected from the group consisting of a straight or branched chainalkylene group having from about 2 to about 20 carbon atoms, acycloalkylene group having from about 3 to about 20 carbon atoms, anarylene group having from 6 to about 20 carbon atoms, and halogenatedderivatives thereof, with a 4-substituted tetrahydrophthalic anhydridehaving a substituent selected from the group consisting of nitro,chloro, fluoro, and bromo, to yield a dianhydride (V) and reaction ofdianhydride (V)

 with diamine (VI) H₂N—R—NH₂  (VI) wherein R is selected from the groupconsisting divalent substituted or unsubstituted aromatic hydrocarbonradicals having about 6 to about 20 carbon atoms and halogenatedderivatives thereof, divalent substituted or unsubstituted straight orbranched chain alkylene radicals having about 2 to about 20 carbonatoms, divalent substituted or unsubstituted cycloalkylene radicalshaving about 3 to about 20 carbon atoms, and divalent radicals of thegeneral formula (XII)

 wherein Q is a divalent moiety selected from the group consisting of—O—, —S—, —C(O)—, —SO₂—, C_(y)H_(2y)— wherein y is an integer from 1 to5, and halogenated derivatives thereof.
 18. The method of claim 17,wherein transimidation with the 4-substituted tetrahydrophthalic anhydride yields 4-substituted N-alkyltetrahydrophthalimide.
 19. Themethod of claim 18 wherein the 4-substitutedN-alkyltetrahydrophthalimide is converted to the 4-substituted N-akylphthalimide for use in the formation of bisimide (IV).
 20. The method ofclaim 19 wherein the 4-substituted N-alkyltetrahydrophthalimide isconverted to 4-substituted N-akyl phthalimide in the presence ofvanadium oxide.
 21. The method of claim 17 wherein the 4-substitutedtetrahydrophthalic anhydride is 4-chlorotetrahydrophthalic anhydride.22. The method of claim 21 wherein the transimidation yieldsN-alkyl-4-chlorotetrahydrophthalimide.
 23. The method of claim 17wherein the N-alkyl-4-chlorotetrahydrophthalimide is converted to4-chloro-N-alkyl-phthalimide for use in the formation of bisimide (IV).24. The method of claim 17, wherein the YI of the dianhydride is lessthan about
 25. 25. The method of claim 17 wherein the alkyl moiety ismethyl.
 26. The method of claim 17, wherein S is derived from bisphenolshaving the formula (VIII

wherein T is a single bond linking the two aryl groups, or a divalent,straight or branched chain alkylene radical having from one to about 20carbon atoms, or a divalent cycloalkylene group having from about 3 toabout 20 carbon atoms, or a divalent arylene group having from 6 toabout 20 carbon atoms, a divalent sulfide, carbonyl, sulfoxide, adivalent radicals of formula (XV)

or a mixture thereof.
 27. The method of claim 26, wherein thebis(phenol) is selected from the group consisting of2,2-bis[4-hydroxyphenyl]propane; 4,4″-bis(4-hydroxyphenyl) diphenylether; 4,4′-bis(4-phenoxy)diphenyl sulfide; 4,4′-bis(4-hydroxyphenyl)benzophenone; 4,4′-bis(4-hydroxyphenyl)diphenyl sulfone;2,2-bis[4-(3-hydroxyphenyl)phenyl]propane;4,4′-bis(3-hydroxyphenyl)diphenyl ether;4,4′-bis(3-hydroxyphenyl)diphenyl sulfide; 4,4′-bis(3-hydroxyphenyl)benzophenone; 4,4′-bis(3-hydroxyphenyl)diphenyl sulfone;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl-2,2-propane;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl ether;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfide;4-(3-hydroxyphenyl)-4′-(4-hydroxyphenyl) benzophenone, and4-(hydroxyphenyl)-4′-(4-hydroxyphenyl)diphenyl sulfone dianhydride, aswell as various mixtures thereof.
 28. The method of claim 17, whereindiamine (VI) is selected from the group consisting of ethylenediamine,propylenediamine, trimethylenediamine, diethylenetriamine,triethylenetetramine, hexamethylenediamine, heptamethylenediamine,octamethylenediamine, nonamethylenediamine, decamethylenediamine,1,12-dodecanediamine, 1,18-octadecanediamine,3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,4-methylnonamethylenediamine, 5-methylnonamethylenediamine,2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine,2,2-dimethylpropylenediamine, N-methyl-bis(3-aminopropyl) amine,3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy) ethane,bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine,bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine,2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine,p-xylylenediamine, 2-methyl-4,6-diethyl-1,3-phenylene-diamine, 5-methyl-4,6-diethyl-1,3-phenylene-diamine, benzidine, 3,3″-dimethylbenzidine,3,3″dimethoxybenzidine, 1,5-diaminonaphthalene, bis(4-aminophenyl)methane, bis(2-chloro-4-amino-3, 5-diethylphenyl) methane,bis(4-aminophenyl) propane, 2,4-bis(b-amino-t-butyl) toluene,bis(p-b-amino-t-butylphenyl) ether, bis(p-b-methyl-o-aminophenyl)benzene, bis(p-b-methyl-o-aminopentyl) benzene,1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide,bis(4-aminophenyl) sulfone, bis (4-aminophenyl) ether1,3-bis(3-aminopropyl) tetramethyldisiloxane, and mixtures thereof. 29.The method of claim 17, wherein diamine (VI) is m-phenylenediamine,p-phenylenediamine, or a mixture thereof.